Somatovisceral intersystemic interactions in newborn rat pups under decreased motor activity

Abstract

Interaction of slow-wave rhythmic components of cardiac, respiratory and motor activities was investigated in newborn rat pups on the first day after birth under normal conditions and after pharmacological depression of spontaneous periodic motor activity (SPMA) induced by injection of myocuran (myanesin) at low (100 mg/pg, i/p) and maximal (235 mg/pg, i/p) doses. The data obtained indicate that in rat pups after birth the intersystemic interactions are realized mainly via slow-wave oscillations of the near-minute or multiminute ranges, whereas the rhythms of the decasecond range do not play a significant role in integrative processes. Injection of myocuran at a dose causing neither muscle relaxation nor inhibition of motor activity induces changes in the cardiac and respiratory rhythms as well as a transitory decrease in the magnitude of coordinating relations mediated by the rhythms of the near-minute and multiminute ranges. The consequences of myorelaxant injection were found to be more significant for intersystemic interactions with the involvement of the respiratory system. The increase in the myocuran dose and, correspondingly, complete inhibition of SPMA is accompanied by the reduction in the slow-wave components of the pattern of cardiac and respiratory rhythms. The cardiorespiratory interactions, more pronounced in intact rat pups, decrease in the near-minute and multiminute modulation ranges and increase insignificantly in the decasecond modulation range.